1. Field of the Invention
The present invention relates to an evaporated fuel adsorbing apparatus for an intake passage of an internal combustion engine.
2. Description of Related Art
Recently, a regulation about HC (hydrocarbon) released from a vehicle when it stops has been changed to be severe, and it has become a problem that when a vehicle temporarily stops, a fuel remaining in an engine cylinder and a fuel leaked from a fuel injector are evaporated and are released from the intake passage to an atmosphere.
In order to suppress release of the fuel, Japanese Patent Publication 2003-193917 proposes an evaporated fuel adsorbing apparatus where an evaporated fuel adsorbing apparatus including an activated carbon layer is disposed downstream of an air cleaner filter in an engine intake passage.
However, with the proposed evaporated fuel adsorbing apparatus, there is such a problem that when hydrocarbons of a large C-number (a number of carbon atoms included in an HC molecule is large, for example, greater than eight) contained in the atmosphere reach the activated carbon layer of the evaporated fuel adsorbing apparatus, the evaporated fuel adsorbing apparatus is likely to lose its primary ability of adsorbing the evaporated fuel flowing to the evaporated fuel adsorbing apparatus from an engine side in a relatively short period of time.